Study objective: To assess the influence of tourniquet inflation-deflation as well as desmopressin and tranexamic acid (TA) administration on prothrombin fragment 1.2, fibrinogen, plasmin antiplasmin complex, and D-dimer concentrations during total knee replacement.
Design: Randomized, placebo-controlled study.
Setting: Large referral hospital.
Patients: 30 ASA physical status I, II, and III patients undergoing total knee replacement.
Interventions: Patients were randomized to one of three treatment groups. Patients received either tranexamic acid, desmopressin, or an equal volume of saline, intravenously.
Measurements and main results: Cubital blood was drawn immediately before induction of anesthesia, 1 hour after tourniquet application, and 2 and 15 minutes after tourniquet deflation. Fibrinogen and D-dimer levels were measured using the Clauss Method and latex agglutination, respectively. Plasmin antiplasmin complex and prothrombin fragment 1.2 levels were measured by enzyme-linked immunosorbent assay (ELISA). All assays were performed in duplicate, and intra-assay variability was documented. No statistically significant difference in fibrinogen, D-dimer, plasmin antiplasmin complex, or prothrombin fragment 1.2 levels was demonstrated among the groups. Similarly, within each group there were no statistically significant differences in the variables studied. However, despite the lack of statistical significance, when compared with their levels during tourniquet application, an increase in D-dimer and plasmin antiplasmin complex levels was observed in all three groups at 2 and 15 minutes after tourniquet release. In contrast, no increase in prothrombin fragment 1.2 generation was noted. Significantly more allogeneic blood was transfused in the Control and Desmopressin Groups when compared with the tranexamic acid group (p< 0.02).
Conclusions: No evidence of tourniquet-induced fibrinolysis or thrombin generation was demonstrated in the systemic circulation. Desmopressin and tranexamic acid had no significant effect on the variables measured.